Melting or Assimilation Processes in Mafic Rocks of Deap-Crust Origins and Generation of Granitic Magma

闪长岩体接触环中的斜长角闪岩中，辉长岩脉至奥长闪长岩脉形成网状结构。辉长岩-石英闪长岩-英云闪长岩-奥长闪长岩脉和寄主贫化角闪岩的场关系、结构、岩石学、主元素和微量元素化学表明，偏铝钙碱性岩浆是由高碱拉斑玄武岩成分的源角闪岩部分熔融形成的。角闪岩在80 0ﾟC和3Kbar以上的水合条件下发生部分熔融，产生角闪岩和奥长角闪岩液体，亏损的角闪岩由角闪石、单斜辉石、钛铁矿和钙质斜长石(AN70-83)组成。辉长岩和石英闪长岩是从英云闪长岩流体中分离出来的堆积物。英云闪长岩流体分异形成更多的硅质英云闪长岩，但没有形成奥长花岗岩。稀土配分模式的理论计算表明，不平衡熔融作用主导了英云闪长岩浆和玄武岩浆的形成。变质英云闪长岩至奥长玄武岩以Eu正异常、低Y和Yb含量为特征，可由中地壳(约10公里)碱性玄武岩的水合部分熔融而成，而不一定是由深部地壳或地幔中转变为榴辉岩的玄武岩熔融而成。

Gabbroic to trondhemitic veins form network strctures in amphibolites in the contact anreole of a dioritic pluton. The field relations, texture, petrography, major and trace elements chemistry of the gabbro-quartz diorite-tonalite-trondhjemite veins and the host depleted amphibolites domonstrate that metaluminous calc-alkaline magmas were generated by the partial melting of source amphibolites of high-alkali tholeiite composition. Partial melting of the amphibolites took place under hydrous conditions of over 800ﾟC and 3 kbar, and produced tonalitic and trondhjemitic liquids, leaving the depleted amphibolites consist of hornblende, clinopyroxene, ilmenite, and calcic plagioclase (An_<70-83> as residual minerals. The gabbro and quartz diorite are cummulates fractionated from the tonalitic liquid. The tonalitic liquid differentiated to form more silicic tonalite, but did not come to trondhjemite. Theoretical calculation of REE patterns demonstrates disequilibrium melting process dominated the formation of the tonalitic and trondhjemitic magama. Metaluminous tonalitic to trondhjemitic magmas, characterized by positive Eu anomalies, and low Y and Yb contents, can be produced by the hydrous partial melting of an alkali basalt in the mid-crust (about 10 km), and not necessarily by melting of basalts transformed to eclogite in the deep crust or mantle.